Seminar Series in Analytic Philosophy 2023-24: Session 9

Beyond Juxtaposition: Mixed Inferences and Anti-Collapse

Carlos Benito-Monsalvo (LanCog, Centre of Philosophy, University of Lisbon)


15 December 2023, 16:00 (Lisbon Time – WET)

Faculdade de Letras de Lisboa

Sala Mattos Romão (Departamento de Filosofia)


Abstract: Logical localism is a thesis within philosophy of logic according to which the correct application of logic is not topic-neutral, domain-neutral or irrespective of subject-matter. That is, logical localism is the thesis stating that different sets of logical principles, forming various alternative logic systems, are required in order to systematically account for correct reasoning in different domains. However, there is a very straightforward problem for anyone defending a localist thesis, a problem that follows from the fact that we reason across domains. This challenge is known as the problem of mixed inferences. The problem is, very roughly, the following: suppose that there are (at least) two components, within the premises or conclusion of an argument, belonging to different domains whose logics are L1 and L2, respectively. Then, which is the criterion of validity for the argument? The approach that I will take consists in trying to solve the problem of mixed inferences (more concretely, the version of the problem raised by Chase Wrenn) by making a finer translation of the arguments and using combination mechanisms as the criterion of validity. Among the alternative methods for combining logics, I will focus on the method of juxtaposition and show that there are some mixed inferences with the logical form of bridge principles that seem to be intuitively valid and that are not validated by juxtaposition, which constitutes an anti-collapse problem for juxtaposition. This limitation is what motivates the improvements on the methods that I propose, as a way of extending juxtaposition and allowing the emergence of the justified bridge principles in the combination mechanisms.